The present invention relates to ice making machines of the type in which an ice mold is refrigerated and water is recirculated from a water receiver over the refrigerated ice mold and back to the water receiver during an ice making cycle, to freeze ice forms on the ice mold, and the ice mold is heated and the water recirculation stopped during an ice harvest cycle, to release the ice forms from the ice mold. At the start of the ice making cycle, the ice mold is rapidly cooled by the refrigeration apparatus to a temperature well below freezing and the water is cooled as it is recirculated over the ice mold. However, before the ice begins forming a clear ice layer on the ice mold, ice crystals are likely to start in the recirculating water and form an ice slush. The time during each ice making cycle at which ice slush begins to be formed appears to be dependent on various factors including the refrigerating capacity of the refrigeration apparatus and hence the rate at which the ice mold is cooled; the temperature of the water from the water supply used to supply an additional quantity of water at the start of each ice making cycle, and the ambient temperature. Different arrangements have heretofore been proposed for overcoming the problem of forming ice slush in an ice making machine. U.S. Pat. Nos. 4,550,572 and 4,785,641 disclose recirculation type ice making machines in which a timing device delays recirculation of water over the ice mold for a predetermined time after the start of the ice making cycle. U.S. Pat. No. 4,715,194 discloses a recirculation type ice making apparatus in which the water distributing means is arranged to leave a predetermined dry zone in which no water is distributed, for the described purpose of causing the dry zone to be somewhat colder than the remainder of the freezing surface to form an ice nucleus for the propagation of ice on the freezing surface.